In the production of yarns for various and sundry textile fabrics and other uses, much attention has been given to finding a method by which certain desirable characteristics of conventional spun yarns, e.g. appearance, bulk and hand, could be imparted to synthetic multifilament yarns. It has previously been proposed, e.g. U.S. Pat. No. 3,946,548, to produce synthetic multifilament yarns having such characteristics by over-feeding the multifilament yarn through a high velocity air jet texturing device whereby the filaments of the yarn are entangled and have loops, bows, coils and the like formed therein. The action of an air jet texturing device on such yarns is well known to persons skilled in the texturing art. The yarn after passing through the air jet texturing device is false twist textured by twisting, heat setting the twist (and the loops, bows, coils and the like formed by the air jet texturing) in the yarn and then untwisting in well-known manner.
In this previously proposed process, the textured yarn is contacted by a friction element, either before the yarn reaches or after it has left the false twist texturing zone, which parts at least some of the filaments of the yarn to produce free filament ends projecting from the yarn. While providing the desired yarn characteristics of appearance, bulk and hand, this process has presented substantial disadvantages. Foremost among these disadvantages is the fact that the strength characteristics of the yarn are materially degraded. This degradation of the strength of the yarn is due to the fact that the friction element may contact and part any of the filaments of the yarn including those filaments which would normally be considered as interior or core filaments. Therefore, the structural integrity of the yarn, normally obtained with continuous filaments, is destroyed and the yarn strength is considerably impaired.